Conventional rotary (angular) position sensors include the analog angle encoder disclosed in U.S. Pat. No. 6,489,761. In the disclosed analog angle encoder, a magnetosensitive device, such as a Hall sensor, was embedded in a central post of a stator. The central post was surrounded by a rotor having a permanent magnet. The output from the magnetosensitive device varied sinusoidally with the rotary angular position of the central flux axis of the magnet with respect to a normal axis of the sensing surface of the magnetosensitive device.
Rotary velocity was obtained in U.S. Pat. No. 6,489,761 by taking the time derivative of a sine/cosine resolver of the rotary angular position. It is noted that the differentiation process introduced undesirable noise and introduced an undesirable phase delay between the actual and computed rotary velocities.
What is needed is an improved rotary velocity sensor and an improved rotary position and velocity sensor.